The general objectives of the proposed research are to develop inelastic scattering of laser light as a useful tool for studying the kinetics of reactions of biological macromolecules; and to apply it, along with other techniques, to problems in bacteriophage assembly and conformational change, chemotaxis, and hydrodynamic properties of complex structures. Two techniques will be of special use in measuring kinetics: electrophoretic light scattering, and rapid determination of scattering autocorrelation functions. The bacteriophages to be studied are T2, T4, and 029. We are interested in studying the kinetics and thermodynamics of such reactions involving them as head-tail joining and disunion, polymerization of tail core and sheath, the slow-fast transition involving the tail fibers, and the binding of dyes to DNA within the phage head. Using E. coli as a chemotactic organism, we intend to apply inelastic scattering to determine such response parameters as mean free walk length, velocity distribution, and time between tumbles. With various structural modifications of phage 029, we will test experimentally the predictions of hydrodynamic theories for complex subunit structures with regard to the translational diffusion coefficient.